superfly
New Member
Hola...
Paging through the forum it looks like series vs. parallel has been pretty well flogged to death, but I'm looking at something a little different.
I have a split system in which most of my house is serviced by a traditional tank heater, and the master bath by a tankless. I recently upgraded the tankless as part of a bath remodel project that includes a large tub and multi-head shower. This heater is more than adequate to service the new stuff all at once, but not large enough to service the other three bathrooms and kitchen that the tank unit takes care of. But the tankless unit will be used about 1.5 hours a day at best, compared to all of the uses of the other system.
I was thinking about connecting the HW output from the tankless unit to the cold water inlet of the tank system, thus running them in series. That way the tank system would never run out of hot water. Endless showers for all. But I don't want to rob capacity from the master bath and ruin a perfect shower or quick bath fill if someone is using water elsewhere in the house. The best fix I could come up with was a flow switch on the line to the master. When hot water in the master is in use, it would supply power to a solenoid valve that switches the inlet to the tank unit from the tankless to the original CW supply. A check valve would prevent it from flowing backward. When not in use, the solenoid valve switches back, resuming tankless supply to the tank heater.
Then I got to thinking; why not put that solenoid valve at the HW output of the tank unit? I can see a few downsides; now the rest of the house will share the same min flow restrictions... And having a tank unit that almost never flows might not be smart. It seems to me that in series is better or I lose the benefit of the hybrid system.
Am I over-complicating this? Does some control valve exist that would do what I want? I know if I buy a second tankless to replace the tank they will work together, but I was hoping for something a little simpler.
Any ideas? Thanks,
Paging through the forum it looks like series vs. parallel has been pretty well flogged to death, but I'm looking at something a little different.
I have a split system in which most of my house is serviced by a traditional tank heater, and the master bath by a tankless. I recently upgraded the tankless as part of a bath remodel project that includes a large tub and multi-head shower. This heater is more than adequate to service the new stuff all at once, but not large enough to service the other three bathrooms and kitchen that the tank unit takes care of. But the tankless unit will be used about 1.5 hours a day at best, compared to all of the uses of the other system.
I was thinking about connecting the HW output from the tankless unit to the cold water inlet of the tank system, thus running them in series. That way the tank system would never run out of hot water. Endless showers for all. But I don't want to rob capacity from the master bath and ruin a perfect shower or quick bath fill if someone is using water elsewhere in the house. The best fix I could come up with was a flow switch on the line to the master. When hot water in the master is in use, it would supply power to a solenoid valve that switches the inlet to the tank unit from the tankless to the original CW supply. A check valve would prevent it from flowing backward. When not in use, the solenoid valve switches back, resuming tankless supply to the tank heater.
Then I got to thinking; why not put that solenoid valve at the HW output of the tank unit? I can see a few downsides; now the rest of the house will share the same min flow restrictions... And having a tank unit that almost never flows might not be smart. It seems to me that in series is better or I lose the benefit of the hybrid system.
Am I over-complicating this? Does some control valve exist that would do what I want? I know if I buy a second tankless to replace the tank they will work together, but I was hoping for something a little simpler.
Any ideas? Thanks,
